Design And Development Of Intelligent Charging Regulated Power Supply

Based on considering the mono-function of power supply in communication devices (i.e. either supplying power at stabilized voltage or charging in application to certain type of battery, not have the intellectualization) at the present time, in this thesis the author has designed an intelligent charging regulated power supply which can be used both to supply power at stabilized voltage and to daily charge and maintain the battery pack used in the overwhelming majority of transmitter-receivers.The paper design develops one kind the switch intelligence voltage-stabilized source which controls by the monolithic integrated circuit, may output two groups of voltages in an outlet choice which uses for the battery of the major part broadcasting station carries on the daily charge and the maintenance ,to the small broadcasting station voltage-stabilized power supply. Discussions on the power supply are mainly carried out from three aspects: switching power supply, charging and discharging of the battery and MCU (Micro Controller Unit) control.Switching power supply: in the present study it is the half bridge hard switching which adopts the PWM (pulse-width modulation) technology. The main parameters of its core devices, such as high-frequency transformer, output choke, etc. are calculated theoretically and some adjustments are made in practice according to the theoretical parameters. In the design of electromagnetic compatibility, shielded transformer and absorbing circuit are adopted. Together with the reasonable layout of the devices the electromagnetic interference is hoped to be minimized and prevented.Charging and discharging of the battery: the output voltage of the power supply varies with the PWM output pulse width, and the output current is adjusted accordingly. The charging impulse is produced through controlling the PWM output. In this way, the output of the power supply is represented as the impulse-type and then the pulse current charge of the battery pack is achieved. The volume of the power supply is limited but the voltages of some battery packs are relatively high, so the discharge resistances whose power and volume are relatively big are needed. With the impulse-type discharging this problem is well solved.MCU control: the power supply uses PIC16F877 MCU as the main control core of the system which monitors the stabilized voltage output of the power supply and gives an alarm if there is something wrong; decides whether the batteries are charged fully; activates the charging and discharging of the battery packs through software; and restores the 'memory' effect of the nickel-cadmium batteries. It realized the intellectualized controlWith the help of instruments and meters the loading test of the power supply is carried out and results show that the efficiency of the power supply is more than 82%; with the 220V alternating current and under the circumstance of full load (24V, 6A) the output ripples and the noises are smaller than 150mV_P-P; and other indexes all reach the designed standard.and results show that the using effects are excellent and all the functions meet the design requirements.Trials in the experiments and military operations have testified that the power source volume small, the efficiency high, the weight is light,also,all the functions of the power supply take effect through the automatic control of the MCU,that is to say, it is intelligentized. In addition, the power supply is accurate to check the charging process, reliable to protect, and adaptive to bad operational environment.